1. Field of Invention
The invention is directed to downhole abrading tools utilized in oil and gas wells to abrade objects within the well and, in particular, to tools that are used to abrade, among other objects, stuck tools, bridge plugs, well tubing, and well casing disposed within the well in which wear of the working profile of the tool is monitored by the detection of signals being emitted from identification tags or emitters disposed on or within the working profile.
2. Description of Art
In the drilling, completion, and workover of oil and gas wells, it is common to perform work downhole in the well bore with a tool that has some sort of wearable working profile interfacing with a downhole structure. Examples include milling a downhole metal object with a milling tool, performing a washover operation with a rotary shoe, cutting through a tubular with a cutting or milling tool, or drilling through formation with a drill bit. During the performance of these operations, it is common for the working profile of the tool, such as cutting elements mounted on its lower or outer face, to wear away. As this wear progresses, the effectiveness of the tool decreases.
Generally, the tool is pulled from the well and replaced when the working profile has experienced a given amount of wear. The degree of wear at which it is desirable to replace the tool depends upon the type of tool and the operation being performed. Often, the decision as to when to pull the tool depends substantially on the experience of the operator. That is, the operator must estimate the amount of tool wear based on whatever is known about the time the operation has been underway, the weight on the tool, the type of downhole structure being worked, the cuttings found in the drilling fluid, or a gradual change in work string torque. None of these parameters, however, provides a definitive indication that the wear in the working profile has progressed to a specific degree at which the operator desires to pull the tool from the well. Pulling a tool prematurely adds unnecessary trips out of the well, adding to rig time and increased costs. Pulling the tool too late gradually decreases the effectiveness of the downhole operation, also adding to rig time and increasing the cost of the operation.